Personal hydrofoil water craft

ABSTRACT

A hull-less personal water craft is provided which reduces air, water, noise, and wake pollution over personal water craft presently on the market. The craft includes a strut assembly having forward and rearward ends, with an operator platform attached at the rearward end, and having at least one hydrofoil positioned below the operator platform. A propulsion system is provided, as is a control column which provides the operator interface when the craft operator is kneeling, standing or sitting on the operator platform. The hydrofoil provides substantially all of the lift for the craft when in operation, and the elimination of a hull greatly reduces the power requirements and wake generated by the craft in operation.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of application Ser.No. 09/771,656, filed Jan. 30, 2001, which is a continuation ofapplication Ser. No. 09/177,622, filed Oct. 23, 1998, now U.S. Pat. No.6,178,905.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention is directed to a watercraft for personalrecreational use, in which the watercraft employs a hydrofoil liftsystem.

[0004] 2. Description of Related Art

[0005] Personal water craft (PWC) vehicles have enjoyed immensepopularity in recent years. PWCs generally allow one, two or more ridersto sit, kneel or stand on the craft and to ride across the surface of abody of water. The popularity of PWCs is also attributable to theconsiderations that they are less expensive than traditional powerboats, are more easily transported over land by smaller trailers, andstorage and maintenance of the PWCs is generally simpler than with fullsize power boats.

[0006] The popularity of such craft, and their operationalcharacteristics, has led to several significant problems. The sheernumber of such craft on some popular bodies of water has led tocongestion, which adversely impacts safety. More significantly, existingPWC designs generate substantial noise, water, wake and air pollution.These PWCs have disproportionately large engines, with current modelshaving 110+ horsepower engines, and, in the quest for increased speed,the power plants are only likely to become more powerful, in the absenceof regulation. The hull form of current PWCs generates substantialwakes, which are a disturbance and a nuisance to other users of thewaterways, and can adversely affect the safety of operating craft, bothPWCs and boats.

[0007] Planing hulls are used in most recreational water craft,including PWCs. The planing hull design has been popularized due to itsability to permit craft operation at speeds in excess of the craft'snatural hull speed. These hulls produce a downward reaction in the waterby impacting the surface of the water with a low aspect ratio wedge,which produces large wakes.

[0008] The problems and costs associated with wake generation cannot beunderestimated. The U.S. Coast Guard regulates speed, and holdsoperators of water craft responsible for damage due to wakes.Enforcement of the regulations is problematic, as wakes from motor boatscan travel large distances before being encountered and causing damage,and identification of the offending vessel is often difficult. Wakes canalso impair the operation and control of other water craft, withresulting detrimental impacts on safety. Wakes further can cause damageto docks and docked water craft.

[0009] The prevalent PWCs employ a water jet as the propulsion means.Water jets are prone to generating large amounts of noise pollution, inthat, due to wave action and the presence of wakes, the PWC frequentlylifts from the water sufficiently to break the intake suction of thejet. Noise volume and pitch increase as a result, due to the jetingesting and expelling air.

[0010] Various other water recreation devices have been employed overthe years, most notably water skis. Many other towed devices, rangingfrom inflated tubes to bicycle style devices employing hydrofoil lifthave been used or proposed for use. U.S. Pat. No. 3,105,249, discloses adevice meeting the latter description. All such devices suffer from thedrawback that a motor boat must be used to propel (pull) the device. Themotor boat, like the PWCs discussed above, is noisy, uses a planing hullwhich creates substantial wakes, and pollutes the water.

[0011] Other water going vehicles have been proposed which employhydrofoils as part of the lift or control system of the craft.Hydrofoils are usually utilized to permit operation of a water craft inexcess of speeds efficiently attainable with conventional hull forms.Often, hydrofoils have been proposed for use with hulled craft, wherebythe craft will travel at low speeds using the displacement of the hull,and, at higher speeds, lifted partially or completely out of the wateron a hydrofoil.

[0012] The high speeds attainable with hydrofoils are accomplished inthat a hydrofoil provides a more efficient means of providing the liftnecessary to float or ride on the water. Conventional displacement hullssimply displace a volume of water equal to the weight of the vehicle.Planing hulls displace water at lower speeds, and, at higher speeds,provide a crude form of lift by impacting the water downwardly,elevating the craft from the water and permitting higher speeds.

[0013] There continues to exist a need for an efficiently operatingpersonal water craft (PWC) vehicle that avoids or minimizes theenvironmental impacts resulting from the widespread use of planinghulled craft. Further, efforts are ongoing to improve the recreationalexperience of such craft, which, in the conventional, planing hull PWCdesign, can largely be achieved only through increasingly powerfulengines to provide increased speed.

[0014] A principal object of the present invention is thus to provide aPWC design which provides many, if not all, of the benefits of existingPWC designs, but which eliminates or significantly reduces the noise,water, air and wake pollution associated with the operation ofconventional PWCs, principally through the elimination of the hullstructure and the reliance on the use of hydrofoil lift for the craft.

[0015] It is a further principal object of the present invention toprovide a PWC design that is more efficient in operation and has muchlower power requirements, for equivalent on-water performance, ascompared with conventional PWC designs.

[0016] It is an additional important object of the present invention toprovide a fast and dynamic vehicle that may operate legally in waterwaysin which other, larger powered water craft have been or may berestricted by laws or regulations limiting the available motor power.

[0017] It is a further object of the present invention to provide a PWCdesign which is convenient and enjoyable to use, and is easy to maintainand transport.

SUMMARY OF THE INVENTION

[0018] The above and other objects of the present invention are achievedby providing a water craft which uses a hydrofoil or a plurality ofhydrofoils as the sole means of suspending the craft operator above thesurface of the water, such that the craft or vehicle can operate withdramatically less power than comparable water craft, such asconventional PWCs. The hydrofoil-based personal water craft of thepresent invention will thus operate with considerably less air, water,and noise pollution, and will generate far less wake than do hulledcraft. The water craft further employs an operator platform designedwith a suitable aspect ratio to provide hydrodynamic lift at startup, toaid in transitioning the craft from its startup position to its runningposition.

[0019] The hydrofoil craft of the present invention includes a mainhydrofoil subassembly including an operator platform on which theoperator will stand, sit, or kneel, and a hydrofoil extending from belowthe platform. This subassembly is coupled to a propulsion system whichis disposed forwardly of the hydrofoil subassembly. The hydrofoil craftis steered and/or controlled by a handlebar-type assembly that extendsrearwardly from a position adjacent to the propulsion system, placingthe handlebars in position to be held by the operator when the operatoris kneeling or standing. The propulsion system itself may be either anaxial flow impeller type, or a ducted propeller type system, and thehandlebar controls for power and steering will be tailored to thespecific type of propulsion unit provided.

[0020] A strut assembly is used to couple the main foil assembly to thepropulsion and steering systems, and the craft thus has no hull.Floatation devices may optionally be secured to the strut assembly,and/or to the operator platform, to give the craft sufficient buoyancyto prevent full submersion of the craft when the craft is idle orstationary.

[0021] The operator platform is designed with a suitable aspect ratiosuch that, at low speeds, it can function as a larger foil to aid inlifting the platform out of the water to achieve running configuration.After providing hydrodynamic lift, as the platform emerges from thewater with an increase in vehicle speed, the platform will temporarilyfunction as a planing surface, until it clears the surface of the waterand becomes completely foil-borne.

[0022] The upper surface of the platform preferably includes a non-slipsurface, in order to provide increased traction for the operator's feet,and also includes small toe and heel (front and rear) cups or chocks toallow the operator to brace his or her feet against the flow of watercrossing the platform.

[0023] The forward-mounted propulsion system may incorporate one or morehydrofoils, in order to provide lift to the propulsion system when inoperation. The forward portion of the craft, namely where the forwardend of the handlebar column is coupled to the propulsion system, alsoincludes hydrofoils to control the depth of, or the elevation of, thefront end and propulsion system while operating at low speeds and atfull speed.

[0024] In another embodiment of the personal water craft of the presentinvention, a main strut couples a motor housing at a forward portion ofthe strut and an operator platform at a rearward portion of the struts,and the motor housing or forward portion of the strut has a foil-bearingstrut depending downwardly therefrom, wherein the foil-bearing strut ispivotable relative to the main strut to allow the distance between themain strut and foil-bearing strut to be varied.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] These and other features, aspects and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings,wherein:

[0026]FIG. 1 is a substantially schematic side elevation view of thehydrofoil water craft in accordance with a preferred embodiment of thepresent invention.

[0027]FIG. 2 is a substantially schematic top plan view of the hydrofoilwater craft in accordance with a preferred embodiment of the presentinvention.

[0028]FIG. 3 is a substantially schematic front elevation view of thehydrofoil water craft in accordance with a preferred embodiment of thepresent invention.

[0029]FIG. 4 is a substantially schematic front elevation view of a mainhydrofoil subassembly in accordance with a preferred embodiment of thepresent invention.

[0030]FIG. 5 is a substantially schematic front elevation view of a mainhydrofoil subassembly in accordance with an alternative preferredembodiment of the present invention.

[0031]FIG. 6 is a substantially schematic front elevation view of a mainhydrofoil subassembly in accordance with a further alternative preferredembodiment of the present invention.

[0032]FIG. 7 is a substantially schematic view of a propulsion systemand the arrangement of the components thereof in accordance with apreferred embodiment of the present invention.

[0033]FIG. 8 is a substantially schematic view of a propulsion systemand the arrangement of the components thereof in accordance with anotherpreferred embodiment of the present invention.

[0034]FIG. 9 is a substantially schematic view of a propulsion systemand the arrangement of the components thereof in accordance with afurther preferred embodiment of the present invention.

[0035]FIG. 10 is a substantially schematic side view of a forward end ofthe hydrofoil water craft of the present invention, showing details of apreferred forward depth control system for the propulsion system.

[0036]FIG. 11 is a substantially schematic side elevation view of themain hydrofoil subassembly illustrating details of a depth controlsystem for the hydrofoil subassembly.

[0037]FIG. 12 is a top plan view of a foil to be employed in the mainhydrofoil subassembly in accordance with a preferred embodiment of thepresent invention.

[0038] FIGS. 13A-C are substantially schematic side elevation views ofthe hydrofoil water craft of the present invention, illustratingoperational details of the pivoting propulsion subassembly.

[0039] FIGS. 14A-D are substantially schematic side elevation views ofthe hydrofoil water craft of the present invention, illustrating theposition of the craft and the operator during a typical take-offsequence.

[0040]FIG. 15 is a substantially schematic view of a propulsion systemand the arrangement of the components thereof in accordance with analternative preferred embodiment of the present invention.

[0041]FIG. 16 is a substantially schematic view of a propulsion systemand the arrangement of the components thereof in accordance with analternative preferred embodiment of the present invention.

[0042]FIG. 17 is a substantially schematic side elevation view of thehydrofoil water craft in accordance with an alternative preferredembodiment of the present invention.

[0043]FIG. 18 is a substantially schematic top plan view of thehydrofoil water craft in accordance with an alternative preferredembodiment of the present invention.

[0044]FIG. 19 is a substantially schematic front elevation view of thehydrofoil water craft in accordance with an alternative preferredembodiment of the present invention.

[0045]FIG. 20 is a substantially schematic view of a propulsion systemand an arrangement of the components thereof in accordance with analternative preferred embodiment of the present invention.

[0046]FIG. 21 is a substantially schematic view of the propulsion systemof FIG. 20 illustrating the manner in which the system rocks thepropulsor.

[0047]FIG. 22 is a front elevation view of internal components of thepropulsion system illustrated in FIG. 20.

[0048]FIG. 23 is a substantially schematic front elevation view of analternative preferred embodiment of the operator platform in accordancewith the present invention.

[0049]FIG. 24 is a substantially schematic side view of the operatorplatform of FIG. 23.

[0050]FIG. 25 is a substantially schematic front elevation view of analternative preferred embodiment of the operator platform in accordancewith the present invention.

[0051]FIG. 26 is a substantially schematic side view of the operatorplatform of FIG. 25.

[0052]FIG. 27 is a substantially schematic side elevation view of thehydrofoil water craft in accordance with a preferred embodiment of thepresent invention.

[0053]FIG. 28 is a substantially schematic top plan view of thehydrofoil water craft in accordance with a preferred embodiment of thepresent invention.

[0054]FIG. 29 is a substantially schematic rear elevation view of thehydrofoil water craft in accordance with a preferred embodiment of thepresent invention.

[0055]FIG. 30 is a substantially schematic side elevation view of analternative preferred embodiment of the hydrofoil water craft of thepresent invention.

[0056]FIG. 31 is a substantially schematic side elevation view of thecraft illustrated in FIG. 30, with the foil strut shown in a retractedposition.

[0057] FIGS. 32A-C are schematic top plan, side elevation and frontelevation views of a saddle-type operator platform according to analternative preferred embodiment of the hydrofoil water craft of thepresent invention.

[0058]FIG. 33 is a substantially schematic side elevation view of analternative preferred embodiment of the hydrofoil water craft of thepresent invention.

[0059]FIG. 34 is a substantially schematic side elevation view of analternative preferred embodiment of the hydrofoil water craft of thepresent invention.

[0060]FIG. 35 is a top plan view according to an alternative preferredembodiment of the hydrofoil water craft of the present invention.

[0061]FIG. 36 is a top plan view according to an alternative preferredembodiment of the hydrofoil water craft of the present invention.

[0062]FIG. 37 is a substantially schematic side elevation view of analternative preferred embodiment of the hydrofoil water craft of thepresent invention.

[0063]FIG. 38 is a substantially schematic side elevation view of analternative preferred embodiment of the hydrofoil water craft of thepresent invention.

[0064]FIG. 39 is a substantially schematic side elevation view of analternative preferred embodiment of the hydrofoil water craft of thepresent invention.

[0065]FIG. 40 is a substantially schematic side elevation view of analternative preferred embodiment of the hydrofoil water craft of thepresent invention.

[0066]FIG. 41 is a substantially schematic side elevation view of analternative preferred embodiment of the hydrofoil water craft of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0067] Referring initially to FIGS. 1-3, a water craft 100 employinghydrofoil lift in accordance with a preferred embodiment of the presentinvention is illustrated. Craft 100 includes a main or rear hydrofoilsubassembly 102, and a forward steering and propulsion subassembly 104,and a strut assembly 106 connected to and extending between the forwardand rear subassemblies.

[0068] In accordance with the present invention, the water craft isdefined as being hull-less. The term hull-less water craft, as usedherein, means a craft having at least one normal operating position forthe rider in which an adult person, when in such operating position, andwhile the craft is at rest in calm water, will necessarily be in contactwith the water.

[0069] The strut assembly illustrated in FIGS. 1-3 is a single strut108, preferably a hollow tube having a circular cross-sectional shape.The strut may preferably be on the order of four inches (4″) indiameter, and made of aluminum or other high-strength, lightweightmaterial which is resistant to corrosion in fresh water and in seawater.Plain carbon steel tubing with a corrosion-resistant paint or coatingcould alternatively be employed, as could a fiber-reinforced plastic orother engineering thermoplastic.

[0070] The rear or main hydrofoil subassembly 102 includes an operatorplatform 110 which is sized to accommodate the feet of the operator (10,FIG. 14B-D), and to permit the operator to kneel comfortably thereon.The platform 110 preferably has a high traction, non-slip surface 112,at least at the central portions where the operator's feet will normallybe placed, although the entire upper surface could be made of a non-slipmaterial, if desired. Platform 110 preferably has front and back footingcleats 114, 116, respectively, secured thereto, with the front cleats114 provided to break the flow of water to minimize the force of anywater flowing across the upper surface of the platform on the operator'sfeet. The back cleats 116 are provided to aid in preventing theoperator's feet from slipping off the platform. The cleats areillustrated in FIG. 1, but are omitted from FIG. 2, in order to show, inFIG. 2, the non-slip surface 112.

[0071] The platform 110 provides several important functions in additionto providing a footing surface. The platform will have on the order ofthirty pounds (30 lbs.) of buoyancy, by virtue of its displacement inthe water, which serves to maintain the rear hydrofoil assembly in aposition close to the surface of the water when the craft 100 is notbeing propelled through the water. Also, due to the length A and width Bof the platform, preferably on the order of about 40 inches or less, and18 inches or less, respectively, and the thin cross-section thereof, theplatform 110 will act as a hydrofoil, providing lift during the initialtake-off of the craft, as will be discussed in greater detail later.

[0072] The aspect ratio of the operator platform is desirably about 1 to2 (2) or greater, in order that sufficient lift is generated duringtake-off. Even more preferably, an aspect ratio of 1 (1 to 1) or greateris desired in order to aid in readily and quickly lifting the operatorplatform to the surface of the water.

[0073] The hydrofoil subassembly further has a pair of foil struts 118secured to the underside of the platform 110, and depending downwardlytherefrom. A main foil 120 is secured at the lower ends of the foilstruts. Rounded ends 119 of the foil struts extend a short distancebelow the main foil 120, in order to reduce vehicle drag whentransporting the vehicle across land, and in order to minimize thepossibility that the foil will ground itself against the bottom of thebody of water.

[0074] The main foil 120 is preferably somewhat greater in length C (onthe order of 48 inches or less) and smaller in width D (on the order of4 inches or less) than platform 110, and the cross-sectional shapethereof is designed to provide lift. The length of the foil struts maypreferably be on the order of thirty inches (30″), thus spacing the mainfoil 120 from the operator platform at that distance.

[0075] The operator platform 110, foil struts 118 and main foil makingup the rear foil subassembly may be made from aluminum, and, in thisinstance the struts may be joined to the platform and to the main foilby welding. Other materials can optionally be employed, includingcomposite materials, injection molded plastics, rotomolded plastics, andeven different materials may be employed for the platform, foil struts,and main foil, i.e., materials selection for the components is not seenas being critical to the construction of a craft 100 in accordance withthe invention. Where other or dissimilar materials are used, otherconventional joining or fastening means, including, for example,riveting, threaded connections, or adhesives, will be readily recognizedas being possible candidates for use.

[0076] The main or rear foil subassembly 102 is secured to strut 108, asby welding, if all aluminum components are employed, or by othersuitable connectors or fastening means. Strut 108 defines a centerlineof the craft 100, as it is connected to the platform 110 at a centerlineof the platform. Foil struts 118 are laterally spaced equidistantly fromstrut 108, and the main foil 120 is centered on the craft as well. Theconnection of the main foil subassembly 102 to strut assembly 106 isreinforced by the provision of a pair of angled support bars 122 rigidlyfastened between strut 108 and the foil struts 118.

[0077]FIGS. 4, 5 and 6 illustrate, in substantially schematic form,alternative preferred configurations for the rear or main hydrofoilsubassembly 102. FIG. 4 shows the subassembly 102 in the configurationshown in FIG. 1, with the operator platform 110, front foot cleats 114,foil struts 118, main foil 120, and also showing the rearward portion ofstrut assembly 106, strut 108 and angled support bars 122.

[0078]FIG. 5 illustrates an alternative configuration in which the onlydifference is that the main foil actually comprises a pair of spacedapart foils 120 a and 120 b attached to foil struts 118. FIG. 6illustrates a single foil construction, but with a centrally disposedsupport bar 122′ connected between strut 108 and the main foil 120. Ascan readily be envisioned from viewing FIG. 6, the centrally disposedsupport bar 122′ may be used as a single foil strut, which constructionwould eliminate the need for side foil struts 118. These variousembodiments are shown to illustrate that the connections and supportsbetween the main body strut 108 and the main hydrofoil subassembly 102are not seen as being critical to proper operation of the craft 100, noris the specific foil configuration.

[0079] Returning to FIGS. 1-3, the strut assembly 106 has a steering orcontrol subassembly and a propulsion subassembly 104 disposed at theforward end of strut 108. While the illustrated embodiments all depictthe propulsion subassembly 104 being located at or near the front end ofthe craft, it is to be recognized that the propulsion may be provided atessentially any position along the length of the craft. Thus, while itis presently believed that providing both the propulsion subassembly andthe steering or control subassembly at the forward end of the craftshould provide the best overall performance, it is not seen as beingcritical that the propulsion subassembly be so located. Certainadvantages in stability and maneuverability are obtained, however, byhaving the steering or control subassembly at or near the forward end ofthe craft.

[0080] Shown schematically in FIGS. 1-3 are a control column 124, havinga handlebar 126 at a distal end thereof, and being operatively coupledto a control housing 128 at a proximal end thereof. A motor housing 130is disposed rearwardly of control housing 128, and underneath controlcolumn 124, and is secured to strut 108 by suitable mounting hardware orwelding. A propulsor housing 132 is disposed at a lower end of controlhousing 128. Details of the construction and operation of, and thecomponents contained within, these housings will be discussed in greaterdetail in the discussion of other drawing figures presented. Ananti-dive plate 134 is preferably provided on control housing 128, whichhas a flat surface area oriented such that, when the forward end of thecraft begins to dive, the plate will impact the surface of the waterwith a positive angle of attack, which will prevent or greatly dampenany further diving motion.

[0081] It can further be seen in FIG. 1 that the control housing 128 isangled toward the rear of the craft, and that the control housing 128and the propulsor housing present a swept-back, rounded nose at thelower extent of the forward end of the craft. This design aids inpreventing the craft from becoming grounded in shallow water and aids intransporting the craft over land.

[0082] The invention described thus far is a hull-less water craft whichis capable of floating in a partially submerged condition when not inmotion, and which, in operation, is lifted in the water by a hydrofoilassembly disposed underneath an operator platform, wherein the hydrofoilassembly bears the weight of the operator and the rear portion of thecraft. The propulsion subassembly propels the hydrofoil, platform andoperator through the water, and the craft is controlled by the operatorby a handlebar control extending rearwardly toward the operator platformfrom the forward control subassembly. Overall, the craft operates as aself-propelled sled.

[0083]FIG. 7 illustrates, in substantially schematic form, a preferredarrangement or embodiment of a propulsion subassembly 134 and otherassociated components. The illustrated subassembly is referred to as asplit propulsion system, in that certain components are housed in motorhousing 130, and other components are housed in propulsor housing 132. Asplit system has the advantage of reducing the size of the housing(propulsor housing 132) that will remain submersed at full operatingspeed. This yields a lower cross-section presented to the water, thuslowering the form and wetted area drag of the propulsion system.

[0084] The selection of which components are positioned in the motorhousing 130 and in the propulsor housing 132 generally follows a logicaldivision of the components required to be submersed in operation, andthose that are not. In FIG. 7, the motor housing 130, which will travelabove the water surface at operating speeds, has a reciprocating motor136, a generator 138 driven by the reciprocating motor, and a fuel tank140 supplying to the reciprocating motor, disposed therein.

[0085] The motor housing optionally has an induction fan 142 in fluidcommunication with the outside environment, which is used to maintain apositive pressure in the motor housing 130. It may also be desirable tofluidly couple the propulsor housing 132 to the motor housing 130, inorder to maintain a positive pressure throughout both housings.Maintaining this positive pressure will provide a moderate boost inengine performance and will make the propulsion system less susceptibleto small leaks, and provides a means of continuously draining sump 166through valve 168.

[0086] Mounting the reciprocating motor 136 in an upper motor housing130 positioned above (as illustrated) or alongside (not shown) the strutassembly 106 desirably allows the interior of strut 108 to house anexhaust system 144, which can include an exhaust resonator 146, amuffler 148, and tubing runs 150 connecting the motor exhaust chamber ormanifold to the exhaust resonator and connecting the resonator to themuffler. In this preferred embodiment, the strut 108 is left open at therear end 109 thereof, as well as at its front end, such that the strut108 is free flooding, and so that the exhaust gases will advantageouslyexit the vehicle at the rear thereof. It is estimated that, due to theability to provide a long, linear muffler 148 in the strut 108, theabove-water exhaust system would achieve approximately the same level ofnoise reduction as would a submerged exhaust port. When the strut 108 isused to house the exhaust system, the motor housing 130 and the strut108 will be joined such that a passage or opening is provided betweenthe two components to allow the connection of the tubing run 150 betweenthe motor 136 and exhaust resonator 146.

[0087] Generator 138 is electrically connected by cable or wiring 152 toa controller 154, which controls operation of electric drive motor 156,and the distribution of power to the motor 156 and battery 158. In thisway, the generator supplies power to the motor 156 through controller154, and also supplies power to battery 158. Battery 158 provides thecharge for ignition, and may also be employed to intermittently providepower in initial takeoff and acceleration modes. The controller 154,battery 158 and drive motor 156 are housed within propulsor housing 132in the FIG. 7 embodiment.

[0088] Drive motor 156 has an output shaft 160 which extends through therear of the propulsor housing, and the shaft 160 is operatively coupledto a propulsor means 162, shown schematically in FIG. 7. The propulsormeans 162 is preferably a ducted propeller or an axial flow impeller,both of which are available in the market, and both of which arerelatively safe and efficient for use in this particular service.

[0089] Drive motor 156 may be jacketed so as to be conduction cooled.Small openings 164 are provided in a lower portion of control housing128 to function as a water inlet, which water is to be collected anddirected to the reciprocating motor 136 and to exhaust system 144(through the open front end of strut 108), for cooling those componentswhile the craft is foil-borne.

[0090] Propulsor housing 132 may preferably be provided with a sump 166at the lower extent of the housing, with a popette valve or anotherselectively openable means. The sump will collect water that enters thehousing, and the water may be drained or forced out through valve 168.

[0091] As shown in this FIG. 7 embodiment, the propulsor housing iscoupled to the craft by a plate 170 that is secured to a lower end of acontrol rod 172. Control rod 172 is mounted inside control housing 128and is rotatable about its longitudinal axis. Control rod 172 is itselfcoupled by a universal joint (shown schematically at reference numeral174), to a steering bar 176 extending within control column 124.Steering bar 176 is coupled to handlebar 126 in a manner such that, whenthe handle bar is pivoted, the steering bar will rotate about itslongitudinal axis, and, through universal joint 174, will cause controlrod 172 and plate 170 to rotate. Steering is thus effected in thisembodiment by rotating the handlebar 126, which, through the describedlinkage, rotates propulsor housing 132 to a desired angle relative tothe longitudinal axis of the craft.

[0092]FIG. 8 depicts another preferred arrangement for the propulsionsubassembly. This arrangement resembles, to some extent, theconfiguration of an outboard motor. This embodiment may preferablyemploy the same exhaust system 144 as in the FIG. 7 embodiment.

[0093] In this embodiment, the pressurized motor housing 130 encloses afuel tank 140 and a motor 136. The output of the motor 136 powers adrive shaft assembly 180, which drives the propeller 162 or otherpropulsor means. A swept-back, rounded, drive shaft housing 182 enclosesa majority of the submersed portion of the drive shaft assembly, and thehousing 182 is pivotably or rotatably coupled at the underside of thecontrol housing 128.

[0094] Control rod 172 in this embodiment is coupled to a rotatablemotor mount 184, by a steering coupling 186, illustrated as a pair ofpulleys 188, 190 and a belt 192 extending between the pulleys. Steeringis effected by rotating the handlebar 126, as in the FIG. 7 embodiment,which causes control rod 172, and pulley 188 connected thereto, torotate. Through belt 192, the second pulley 190 is rotated, whichrotates the drive shaft housing 182, drive shaft assembly 180 andpropeller 162.

[0095] A further preferred propulsion subassembly configuration isillustrated in FIG. 9. This configuration replaces the rigid, geareddrive shaft assembly 180 shown in FIG. 8 with a flexible drive cable orshaft 196. The use of the flexible drive shaft 196 enables the use ofthe simpler steering system shown in FIG. 7. In this embodiment, driveshaft housing 182 is coupled to a control rod 172 at a lower plate 170attached thereto. Rotation of the drive shaft housing 182 and propeller162 to effect steering takes place in a manner similar to the manner inwhich propulsor housing 132 is rotated in the FIG. 7 embodiment.

[0096]FIG. 10 illustrates a preferred embodiment of a forward endpropulsion system depth control system 200. The depth control system 200employs one or more pivotable foils 202 (one shown) extending laterallyfrom opposite sides of control housing 128. The foil or foils 202 arepreferably pivoted at their center of lift, and the pivot means can be apin or pins extending from the foils 202 through the walls of controlhousing 128. The angle of attack of the foils 202 is controlled bysensor 204, which includes a large, inclined sensor plate 206 attachedto an arm 208 pivotably secured to control housing 128. Arm 208 isconnected to one or both of the foils 202.

[0097] As shown, in a preferred embodiment, the plate 206 and arm 208,and the foils 202, are in a substantially neutral position, i.e.,substantially parallel to the surface of the water, when the propulsorhousing and the front of the craft are traveling stably at approximatelythe desired depth. Plate 206 is designed such that it will substantiallyskim the surface of the water. Thus, as the front end of the vehiclebegins rising farther out of the water, plate 206 will descend, pushingdownwardly on the front of the foils 202, by action of the pivoting arm208, to position the foils to have a negative angle of attack. The foilsthus impart a downward force on propulsor housing 132, substantiallypreventing it from rising any higher in the water. The ability togenerate the negative angle of attack is an important and significantfeature, in that the operator on platform 110 may have a tendency tolean back and/or pull back on handlebars 126, both of which will tend tocause the craft to attempt to raise the front end thereof. The depthcontrol system will, in all conceivable instances, be capable ofretaining the front end in the water.

[0098] When the front end of the vehicle begins to descend past thedesired neutral position, plate 206 pivots upwardly, causing arm 208 topull upwardly on the front of foils 202, thus providing a desiredpositive angle of attack to substantially prevent further descent of thefront end, and to urge the front end back to the neutral position.

[0099] A damper foil 212 and arm 214 may preferably be secured to arm208 at the side of pivot point 210 to which plate 206 is attached. Thedamper foil 210 will be positioned to remain submerged during normaloperation, and will damp or stiffen the sensor 204, making it lesssensitive to wave action or other water surface level transients.

[0100]FIGS. 11 and 12 illustrate features that may advantageously beincluded on the rear foil subassembly 102, in order to provide depthcontrol for the foil and rear portion of the craft. More specifically,these figures show the use of ventilation means provided to reduce thelift of the foil, and thus to regulate the minimum depth (maximumheight) attained by the foil in operation.

[0101] In FIG. 11, a ventilation tube 220 is shown extending upwardlyfrom the upper surface 121 of foil 120, alongside foil strut 118. Anidentical ventilation tube would be similarly positioned on the secondfoil strut (not shown). The low-pressure region present on the top ofthe lifting foil 120 is used by tube 220 to induct air from above thesurface of the water to the top of the foil. This air induction, alsoreferred to as ventilation, has the effect of dramatically reducing thelift generated by the foil.

[0102] Thus, in the present invention, the ventilation tube 220, whenfully submerged, has no substantial ventilating effect, and the liftprovided by the foil will raise the foil 120 and the operator platform110. The length of the ventilation tube 220 is selected such that anupper end 222 thereof breaks the surface of the water when the foil 120reaches a predetermined level below the surface of the watercorresponding to the desired closest distance of approach of the foil tothe surface of the water, and the desired elevation of the platform 110in operation.

[0103] When the upper end of the tube breaks the surface, ventilationcommences, thereby dramatically reducing lift. As a result, the foilwill remain substantially at that level in the water. At this position,the top of the tube will spend a portion of time exposed to the air anda portion of the time submerged, due to the natural action of crossingeven small waves or wakes. This has the effect of providing a smoothtransition from the normal to the ventilated condition. The ventilationsystem becomes more effective at higher craft speeds, due to theincreased tendency of the vehicle to climb, with even the minimal liftprovided by the ventilated foil.

[0104] The opening at the lower end 224 of the tube is preferablypositioned immediately adjacent the upper surface of the foil, and maypreferably face laterally toward the side of the craft, or rearwardly,away from the flow of water. This will ensure a reliable low pressurecoupling of the opening to the foil.

[0105]FIG. 12 illustrates a further preferred embodiment of theventilator system. In this figure the ventilator tubes 220 arepositioned inside, or are made integral with, foil struts 118. Inaddition, a ventilator extension tube 226 extends laterally within theinterior of foil 120, and has a plurality of orifices 228 extendingthrough the upper surface 121 of the foil, which will bleed air inductedthrough ventilator tubes 220 to the upper surface of the foil. Thisconfiguration is expected to increase the effectiveness of theventilation.

[0106] The two ventilator tubes 220 could communicate with the entireventilator extension tube, or, preferably, the ventilator extension tubewill comprise two separate tubes 230, 232 and each ventilator tube 220may be in fluid communication with only the portion of the extensiontube 226 on the side of the craft on which the respective ventilatortube 220 is disposed. This arrangement can provide a limited amount ofroll control, in addition to or as an enhancement to the depth control,in that, if one side of the craft is raised higher, for example, withthe operator leaning considerably to one side, the ventilator on thatraised side will operate to decrease lift on the foil on the raised sidethereby tending to right the craft, while the ventilator on the lowerside will not be significantly decreasing lift on the opposite side.

[0107] FIGS. 13A-C illustrate a further feature of the propulsion andsteering system in accordance with a preferred embodiment of the presentinvention. In these figures, the propulsion and steering system isassembled to the main strut subassembly 106 such that the propulsorhousing and propeller can pivot or rock relative to the strut 108, andsuch that the longitudinal axes of these components will not always bein parallel.

[0108] The main object of providing a rocking propulsion subassembly isto facilitate the initial take-off of the vehicle, as will be discussedin greater detail below. Referring now to FIGS. 14A-D, a typicaltake-off sequence is illustrated schematically. With no operatoronboard, the vehicle or craft 100 is partially buoyant, with portions ofthe craft extending above and below the surface of the water, as seen inFIG. 14A. The operator 10 mounts or boards the craft 100 preferably bykneeling or crouching on the operator platform 110, as shown in FIG.14B. In this position, the forward end of the craft remains near thesurface of the water, while the operator platform 110 lowers under theweight of the operator.

[0109] The operator 10, using the controls disposed on handlebar 126,starts the craft moving in the water, whereupon the rear foilsubassembly and the lift provided by the operator platform 110 cause therear portion of the craft to rise such that the operator platform breaksthe surface of the water, as seen in FIG. 14C. Further increases incraft speed result in a further raising of the operator platform due tothe lift provided by foil 120. In full operation (FIG. 14D), theoperator platform 110, motor housing 130, and strut assembly 106 travelabove the surface of the water, due primarily to the lift provided bymain foil 120, with lift also contributed by foils 202 attached to thepropulsor housing 132.

[0110] Returning now to FIGS. 13A-C, the components enabling thepropulsor housing 132 to be rocked during take-off will be described.Control column 124 is pivotably connected to control housing 128 by asuitable hinged connection 230 (see also FIG. 7) or other means. Thispivotable connection is desired even when the rocking propulsor housingis not employed, so that the handlebar 126 can travel between a loweredposition and a raised position, to enable the handlebars to be heldcomfortably when the operator is kneeling or standing, and toaccommodate a range of operator heights.

[0111] Where a rocking propulsor is used, the propulsor housing 132 ishingedly connected to the steering mechanism (plate 170 in FIG. 7) byhinge means 232. This connection is made at the rear portion (aft ofcenter) of the propulsor housing. A rod or cable 234, shownschematically in FIG. 13A, is secured to the control column 124 at apoint which will pivot upwardly when the handlebar at the end of thecontrol column is pivoted downwardly, or is at a lowered position (FIG.13B). The opposite end of rod or cable 234 is secured to the propulsorhousing 132 at a point rearward of the hinged connection. Thus, when thehandlebar is lowered, the rod or cable pulls the rear portion of thepropulsor housing upwardly, and, when the handlebar 126 is raised, thepropulsor housing is able to pivot back into its normal orientation orposition. The propulsor housing preferably would have a biasing means toretain it in contact with plate 170 in the absence of a substantialdownward force being applied to the handlebar 126 and control column124.

[0112] The rocking propulsor housing facilitates an easier andpotentially quicker take-off for the craft. In the at-rest position(FIG. 13B), the vehicle, with an operator or rider 10 in place, ispitched upwardly. While this has the benefit of angling the foils tobetter generate lift, the propulsor housing 132, if not pivotable, wouldalso be similarly upwardly pitched. This would cause the propulsorsubassembly to have a tendency to broach the surface of the water, whichcan cause the propeller 162 to ventilate with air, and thereby losethrust and efficiency.

[0113] Maintaining the handlebar 126 and control column in the loweredposition will raise the back end (and lower the front end) of thepropulsor housing, as seen in FIG. 13B. This will decrease the relativepitch of the propulsion system to the surface of the water, and willdirect the thrust generated by the propeller directly at the undersideof the operator platform 110. In the take-off sequence, operatorplatform 110 provides lift while emerging from the water, and thepropulsion thrust thus boosts the lifting forces acting on the platform.This results in the operator and platforms being more easily liftedprior to the craft's achieving higher speeds. Since less of the operatorwill be in the water creating drag, the vehicle can be propelled forwardwith less power. Finally, the thrust of the propeller will be moreclosely in line with the desired direction of motion, thereby maximizingthe use of the thrust to propel the craft forward.

[0114] The propulsor section would preferably be able to pivot on theorder of about 10-20 degrees from its normal position, but this can bevaried to accommodate specific geometries of the craft.

[0115]FIGS. 15 and 16 illustrate two alternative preferred arrangementsof a fully submersed propulsion subassembly, which could be employed inplace of the partially submersed or split systems illustrated in FIGS.7-9. The principal differences between the two embodiments in FIGS. 15and 16 are the type of drive motor and auxiliary equipment employed.

[0116] In FIG. 15, a pressurized propulsion enclosure 300 is provided.In this configuration, an electric motor 302 is used to power a ductedpropulsor 304. Electric motor 302 is, in turn, powered by a gas-poweredmotor/generator combination 305, 306. The motor 305 has an exhaust port307 extending through the wall of the enclosure. The generator outputcan drive the electric motor directly and/or can be stored in battery308 under the control of charge controller 310. Fuel for the gas-poweredmotor is stored in fuel cell 312.

[0117] The use of this power plant configuration provides highefficiency, lower gas motor power requirements, allowing use of asmaller gas motor, and a built-in thrust reverse capability. The craftmay also be operated on battery power alone intermittently, allowingextremely quiet operation, and limited “get home” operation in the eventof a gas motor failure.

[0118] The propulsion enclosure 300 may also be provided with a snorkeltube 314 to allow air to be inducted into the enclosure by the motor,thereby allowing the enclosure to operate as a compressed air plenum forsupercharging the gas motor. Enclosure 300 may be mounted to theunderside of the strut subassembly by a pair of propulsion supportstruts 316, 318.

[0119] The FIG. 16 embodiment is a gas engine powered system. Propulsionenclosure 400 contains a gas engine/motor 402, a fuel cell 404, astarter motor 406 and battery 408 used to power the starter motor. Themotor output is used to power the propulsor 410. As in the FIG. 15embodiment, the propulsion enclosure has a snorkel tube 412, and anengine exhaust port 414. While this configuration may be somewhat lessefficient than that illustrated in FIG. 15, it may be less expensive toconstruct. Overall, submersing the entire propulsion system in either ofthese arrangements offers the benefits of better sound isolation, lowerfoil lift requirements, and greater inherent stability.

[0120] FIGS. 17-19 illustrate an alternative preferred configuration ofthe personal water craft 500 of the present invention. The principaldifference between this embodiment and the embodiment illustrated inFIGS. 1-3 is the construction of the strut subassembly 506. In thisembodiment, the craft still has a forward propulsor housing 532, acontrol housing 528, control column 524, handlebar 526, rear operatorplatform 510 and rear foil assembly 502, including main foil 520.

[0121] Strut subassembly 506 in this embodiment comprises a pair oflaterally spaced struts 508L, 508R (FIGS. 18, 19) that connect thepropulsor subassembly 104 to the foil subassembly 102. Each of struts508L and 508R is made up of strut sections, a forward section 550L,Rwhich connects to the control housing 528, and branches to the left orright, respectively, a middle longitudinal section 552L,R, connected toand extending from the forward sections to rear sections 554L,R. Rearsections 554L,R connect to the rearward end of middle sections 552L,R,and to the underside of operator platform 510, at the point where foilstruts 518 connect. Auxiliary foil struts 522 also connect to therearward end of middle sections 552L,R, and to a lower end of foilstruts 518.

[0122] The craft of the present invention is on the order of ten (10)feet in overall length, and the height from the main foil 120 to theoperator platform 110 may be on the order of about 30 inches or less.The span of the main foil 120 is preferably 48 inches or less, with theoperator platform preferably being several inches less in span than themain foil. The craft thus is of a manageable size for a single user, andcan readily be trailered in a manner similar to the current traileringof the hulled personal water craft now on the market.

[0123]FIGS. 20 and 21 illustrate a further preferred embodiment of thepropulsion subassembly of the present invention. FIG. 22 is a frontelevation view of certain internal components of the propulsionsubassembly.

[0124] This propulsor subassembly 600 includes a control housing orstrut 602 and a propulsor housing or gear housing 604 which ispositioned below the control housing. Control housing or strut 602 issecured to the forward end of the craft (not shown in FIGS. 20, 21) anddepends downwardly therefrom.

[0125] Extending through control housing 602 is a drive shaft 606,coupled at its upper end to an output of a motor. Drive shaft 606 isoperatively coupled to ducted propulsor 608 by a bevel gear pair 609,which comprises drive gear 610 and driven gear 612. Drive shaft 606 mayinclude a universal joint or a flexible coupling (shown schematically inFIG. 22 at reference numeral 611) connecting it to bevel gear 610, sothat the drive shaft can continue to drive the gear pair when thepropulsor housing is rocked or pitched, relative to the drive shaft. Thedriven gear 612 of the gear pair is connected to the propulsor 608 by adriven gear shaft 614, which is connected to driven gear 612 and extendsfrom the interior to the exterior of propulsor housing 604.

[0126] The propulsor housing or gear housing 604 is coupled to thecontrol housing or strut 602 by means of a control disc 620 captured ina channel 622 of a bracket 624, the bracket being secured to an upperinner wall of the propulsor or gear housing 604. Control disc 620 iscircular (actually, a short cylinder), and has a pair of spaced forkmembers 626 extending perpendicularly upwardly from an upper surface 628of the disc. The fork members 626 are connected by pins 630 to thecontrol housing 602, which allows the fork members to pivot relative tothe control housing, thereby pivotably securing the propulsor or gearhousing 604 thereto.

[0127] A rocking control cable 632, illustrated as a sleeved controlcable, is connected to the control disc 620 at a point to the aft of thefork members 626. The rocking control cable can be operated by push/pullcontrol rods or arms (not shown), and can move the propulsor or gearhousing from a normal, non-rotated axial orientation (FIG. 20) to arotated orientation (FIG. 21), by pulling upwardly on the rear of thecontrol disc 620. The control disc 620, in turn, rotates bracket 624 inwhich it is captured, thereby rotating the propulsor or gear housing 604and propulsor 608. It is expected that it will be undesirable to allowthe propulsor housing to be rocked or rotated in the opposite direction,i.e., with the propulsor 608 oriented to provide upward thrust, and, inthat case, a stop element 634 may be mounted to the inner wall ofcontrol housing 602 as schematically illustrated in FIGS. 20 and 21,with the stop 634 preventing the fork members 626 from moving rearwardlypast the upright or vertical orientation.

[0128] This propulsor subassembly also provides for steering control, byproviding a tang or flange 636 projecting upwardly from the uppersurface 628 of the control disc 620. A steering control cable 638 maypreferably be attached to tang 636, and, when the cable is manipulatedby the rider, the tang is pushed or pulled, thereby causing the controldisc 620 and propulsor or gear housing 604 to rotate from side to side.

[0129] The controls for the rocking and steering of the propulsor orgear housing need not be sleeved cables of the push/pull type, butinstead may comprise hydraulic controls or other suitable control means.

[0130]FIGS. 23 and 24 are front and side views, respectively, of anoperator platform in accordance with an alternative preferred embodimentof the present invention. In this embodiment, platform 110 is equippedwith a saddle-type seat 300, made up of two side panels 302 and anupper, contoured seat panel 304. In this embodiment, an operator wouldhave the option of standing, crouching, or being seated while operatingthe craft.

[0131] The saddle-type seat in the illustrated embodiment has a channel306 extending therethrough to permit water to pass through when theplatform 110 is not completely elevated out of the water.

[0132]FIGS. 25 and 26 are front and side views, respectively, of anoperator platform in accordance with another alternative preferredembodiment of the present invention. In this embodiment, platform 110 isequipped with a bicycle seat 310 elevated above platform 110 andsupported by seat strut 312. Both the saddle-type seat and the bicycleseat configurations are perceived as being desirable primarily as afunction of customer preference, and the addition of either seat to theoperator platform is not seen as having any dramatic impact on theoperation of the craft.

[0133] FIGS. 27-29 are side, top and rear views of a further preferredembodiment of the craft of the present invention. In this embodiment,the operator platform 410 is not entirely substantially planar, butrather has two wing sections 412, 414, and a raised central saddlesection 416.

[0134] As can be seen by comparing this embodiment to the FIG. 23embodiment, which adds a saddle seat to the planar operator platform110, the embodiment shown in FIGS. 27-29 simply forms the footingelements (wing sections 412, 414) integrally with the saddle portion(saddle section 416). In making this a unitary component, it can beseen, in FIG. 29, that a central planar portion of the operator platform110 may be omitted, and the operator platform 410 may be secured tostrut 108 by one more platform struts 418 (two shown).

[0135] It can be seen in FIG. 28 that the operator platform 410 isprovided with several areas of non-skid surfaces, including footingsurfaces 420, seating surface 422, and crouching surfaces 424. Thecrouching surfaces are positioned to engage the inside of the knee,thigh and/or calf, of the rider. The non-skid surfaces provide tractionand increased stability for the rider, in the available operatingpositions, which primarily include standing, sitting andcrouching/kneeling. A saddle-type operator platform will allow the riderto closely conform his or her body to the operator platform (see FIG.27), thereby streamlining the body and reducing drag during the takeoffsequence.

[0136] As noted previously, the operator platform of the presentinvention preferably has an aspect ratio of at least about 2, and morepreferably at least about one (1). In the FIGS. 27-29 configuration, theaspect ratio would be measured using the dimensions of the wing sections412, 414 extending laterally of the saddle section 416, as the wingsections will primarily be responsible for the lift provided by theoperator platform during startup. By comparison, the aspect ratio of aplanar platform, such as platform 110, will be measured using theoverall dimensions of the platform.

[0137] An alternative preferred embodiment illustrated in FIGS. 30-36,provides several improved characteristics over the preferred embodimentsdiscussed above. In the previously discussed preferred embodiments, theoverall height of the vehicle is substantial, because the foils projectbelow the water craft a considerable distance, in order to operateefficiently. When a saddle-type operator platform is employed, thisplatform extends upwardly to approximately half the height of theoperator, resulting in an overall craft height of approximately five (5)feet. Such a configuration can limit the ability to routinely and easilybeach the vehicle, and may increase the chances that the vehicle willbecome damaged in use, or may result in increased chances of loss ofcontrol of the vehicle or injury, in the event that the craft strikes anobstruction.

[0138] In addition, the drag and propulsion efficiency of the foregoingembodiments during takeoff can be improved upon. These factors are veryimportant in sizing a power plant for the craft, and can affect therelative size and pitch of the propulsor to be used on the craft. Aconfiguration that reduces drag and increases propulsion efficiency attakeoff can employ a smaller power plant, and the propulsion systemoverall can be optimized for fuel economy, increased top speed, or otheroperating parameters.

[0139] The preferred embodiments of FIGS. 30-36, address these designconsiderations and provide improvements over the previously discussedembodiments in these respects. The provision of a foil strut that iscapable of pivoting or rotating upwardly toward a main strut addressesthe situation presented by having the foil or foils fixed in position ata considerable distance below the operator platform. The pivoting strutis expected to reduce the potential for loss of control of the vehicleor injury to the operator or others in the vicinity of the craft.

[0140] Turning first to FIG. 30, the hydrofoil water craft 700 of thisalternate preferred embodiment is shown in substantially schematic form.The craft 700 has a main strut assembly comprising a main strut 702 anda motor housing 706, wherein the main strut operatively couples anoperator platform 704 at a rearward portion of the main strut 702 to themotor housing 706 at a forward portion of the strut.

[0141] As illustrated, motor housing 706 is coupled to main strut 702such that the motor housing can rotate or pivot about a horizontal axiswhich is perpendicular to an axial extent of the craft. This couplingmay be effected in any known manner, including the use of pins extendinglaterally from the sides of the motor housing into bores or bearingstructures provided on main strut 702.

[0142] Foil strut 708 is coupled to, and extends downwardly andrearwardly from, motor housing 706. In the embodiment illustrated inFIG. 30, foil strut 708 is substantially rigidly secured to motorhousing 706, and will thus pivot or rotate relative to main strut 702when motor housing 706 so pivots or rotates. In an alternativeembodiment (see, e.g., FIG. 37), motor housing 706 may remain fixedrelative to the main strut, with the foil strut being pivotably mountedto a pivoting means 750, shown here in the form of a short leg 750extending downwardly from the fixed motor housing, as will be readilyrecognized by those of ordinary skill in the art.

[0143] The craft 700 in FIG. 30 further has a control column 710 withhandlebars 712 protruding therefrom. As illustrated, a brace 714 isshown as being attached to the control column 710 and to the motorhousing 706, thereby operatively linking these members together. Brace714 allows the operator to control the position of the motor housing 706and foil strut 708 relative to main strut 702 by raising or lowering thecontrol column 710, which is itself pivotably mounted to main strut inthe illustration of FIG. 30.

[0144] The control column is mounted at a forward portion of the mainstrut 702, but rearwardly of the position at which the motor housing 706is mounted to main strut 702. The control column 710 may preferably havea slot 711 which brace 714 engages, which provides for a predeterminedrange of rotation or pivoting of control column 710 without an attendantmovement of housing 706. This allows the positioning of foils 720 usingthe control cables 722 without releasing the clutch.

[0145] Brace 714 allows the operator to optionally deploy (lower) orstow (raise) the foil strut by rotating the motor enclosure to which itis attached. In a preferred embodiment, the mechanism of slot 711 wouldfunction to release a clutch, shown schematically at 715, holding theposition of motor enclosure 706 fixed in relation to the main strut 702by preventing the rotation of the axle or bearings between main strut702 and motor housing 706.

[0146] Thus, it can be seen that the interaction of the brace 714 andslot 711 provides a range of motion for control column 710 in which thefoil position control 722 will be active, but the foil strut control 714is not releasing the clutch, and the motor housing will thus not rotate.This gives the operator the freedom to control the elevation of thevehicle over the water while in operation, including the possibility ofexecuting jumps.

[0147] When the brace 714 travels to the ends of slot 711, the mechanismwill trigger a release of the clutch, possibly by the use of switches orsensors, and allow control column 710 to be used to rotate the motorhousing. The clutching mechanism may also preferably be designed sothat, upon experiencing a sudden and excessive load, e.g. the foil strut708 striking an object, the clutch will automatically release and allowthe foil strut to rotate, thereby minimizing the disruptive effect ofthe impact.

[0148] The foil strut 708 of craft 700 is preferably in the form of atube having a passage extending therethrough. At least one, andpreferably more than one, lift foils 720 are pivotably mounted on thefoil strut 708 at spaced apart locations. The lift foils 720 extendlaterally of the foil strut, and are sized to present a desired aspectratio.

[0149] The positioning or orientation of the lift foils 720, in theillustrated preferred embodiment, is controlled by a control cable 722having one end secured to a lower portion of control column 710, andhaving other portions secured to foil control members 724 at theappropriate locations along the length of the cable. Movement of thecontrol column will thus push or pull the control cable 722, dependingupon the direction of movement thereby pivoting the foils allowing theoperator to control the elevation of the vehicle over the water.

[0150] Also, it can be seen in FIG. 30 that the control column 710 canbe manipulated by the operator, who would be standing, kneeling orsitting on the operator platform 704, to raise or lower the foil strut708 and to pivot foils 720, as desired. This facilitates handling thecraft near a shoreline or other shallow water areas, for example. Theoperator, in anticipation of bringing the craft 700 into shore, orbeaching the craft, can push upwardly on the handlebars 712 and controlcolumn 710 to cause clutch to release, and the motor housing to tiltforward, which in turn causes the foil strut to rotate upwardly towardthe main strut 702. Moving the foil strut 708 upwardly in this mannerallows the craft to clear submerged obstacles or to more closelyapproach dry land before the foil strut contacts the sand or earthunderlying the water at the shoreline.

[0151]FIG. 30 also shows, in substantially schematic form, a propulsionmeans 730 disposed at the end of foil strut 708 opposite the end of thefoil strut which is operatively connected to motor housing 706. As ashorthand notation, the end of the foil strut 708 connected to the motorhousing will be termed a proximal end 707, and the end at which thepropulsion means 730 is disposed will be termed a distal end 709. Thepropulsion means may be a propeller 732 (as shown schematically in FIG.30), a propulsor, as described elsewhere in this specification, or othersuitable means for providing thrust to move the craft forward.

[0152] The propulsion means is powered by a motor (not shown) housedwithin the motor housing 706. A propulsion transmission meansoperatively couples the motor output to the propulsion means 730, andmay preferably be integral to the foil strut 708, for example, by use ofa drive shaft housed within the foil strut. Alternatively, where apropulsor is used in lieu of a propeller as the propulsion means 730,the motor output may preferably be used to pump water through the foilstrut 708 to the propulsor.

[0153] Turning to FIG. 31, the water craft 700 is shown in analternative preferred configuration. This configuration employs anoperator platform 704 that is formed as a saddle seat 740. FIGS. 32A andB show top plan and side elevation views, respectively, of an exemplarysaddle seat 740. A saddle seat is seen as providing several significantadvantages when used in combination with the movable or rotatable foilstrut 708. It can be seen in FIG. 31 that the foil strut can be sizedsuch that, as it rotates toward the main strut 702, the propulsion means730 mounted at the distal end 709 of the strut travels into a recess 742formed under the saddle seat 740. This has the effect of shielding thepropulsion means, which can aid in protecting the operator and possiblyswimmers in the water, should the operator accidentally come upon aswimmer while riding the water craft.

[0154] Optionally mounted on the operator platform within recess 742 isfoil 743, which has the purpose of providing additional lift when thepropulsion means 730 is recessed. This lift is generated by theimpingement of the ejected water from the propulsion means 730 on thefoil 743. An additional feature of foil 743 is to further enclose thepropulsion means 730 while it is in its retracted position. The liftgenerated by foil 743 may be useful in other alternative embodiments ofthe invention, for example, one which includes motorized deployment offoil strut 708 while the vehicle is in motion, particularly duringtakeoff. The additional lift will lift the operator partially from thewater, greatly reducing drag during takeoff. Once sufficient speed hasbeen gathered, the foil strut 708 could then be deployed (lowered) usinga small motor or other mechanical assist device. One approach toeffecting this would be the provision of foil strut position controller,shown schematically at 755 (FIG. 34), which preferably would be a smalljack screw motor, recessed within slot 754, which would move brace 752(FIG. 34) forward to deploy the foil strut 708. A hydraulic ram could beprovided in place of the jack screw motor as the foil strut positioncontroller 755, to provide the same function.

[0155] The saddle seat 740 forms the recess underneath by using a moldedor formed hollow shell-like construction which provides an upper seatingsurface 744 (FIG. 32A) and an essentially arched interior surface 745(FIG. 32C). Preferably, footrests 746 are secured to, and extenddownwardly and outwardly from the saddle seat 740.

[0156]FIG. 33 schematically illustrates an alternative approach tocontrolling the rotation of the motor housing and foil strut. Thisfigure shows that a ratchet-type latching mechanism can be employed,such that a plurality of pre-set orientations of the motor housing706/foil strut 708 may be selected by the operator of the craft, by wayof engagement of teeth or cogs 705 protruding from the surface of motorhousing 706, with a latch or pawl 713 disposed on control column 710. Itwill be appreciated that this latching mechanism will preferably bedesigned such that the latching mechanism will disengage or release toallow the foil strut 708 to pivot toward the main strut 702, in theevent that the foil strut 708 strikes or impacts a submerged object.

[0157] It will also be readily appreciated that other forms of operatorcontrol of the orientation of the motor housing/foil strut may also beused. Examples include geared mechanisms and friction brakes.

[0158] Some alternatives to manual control of the foil strut rotationdepicted in FIG. 30 are illustrated in FIGS. 38-41. In FIG. 39, ahydraulic ram 780 is attached to main strut 702 and to foil strut 708.In FIG. 40, the hydraulic ram 780 is connected to the main strut 702 anda pivotable motor housing 706. The hydraulic ram extends and contractsto change the position of the foil strut 708 relative to the main strut702 and operator platform 704.

[0159]FIG. 41 illustrates an alternative preferred embodiment in whichthe motor housing 706 and foil strut 708 are constructed such that theyare biased, as by counterbalancing or a spring or springs, into theretracted or raised position (closest position to the main strut 702).The foil strut position may then be controlled via a cabling arrangement782, wherein the cable counteracts and overcomes the initial biasingforce, such that the foil strut may be deployed or lowered to a desiredposition. Reverting back to FIG. 33, the cogs 705 could be engaged by amotor driven worm gear to raise and lower the foil strut.

[0160] In each of the embodiments shown in FIGS. 38-41, the operatorinterface will present to the operator controls for the actuators tooperate these assist devices. The controls may be switches or buttonsmounted on control column 710, or the handlebar 712, or elsewhere on thecraft, preferably in a position or positions where the operator willhave convenient access.

[0161]FIG. 37 illustrates a further variant of this alternativepreferred embodiment. In this configuration, motor housing 706 insecured in a substantially fixed position relative to main strut 702 onthe main strut assembly. The foil strut 708 is, on the other hand,coupled to motor housing 706 in such a manner that it is pivotablebetween an extended position spaced below the operator platform 704 andmain strut 702, and a retracted position in which the foil strut hasmoved upwardly toward the operator platform and main strut.

[0162] The foil strut may be pivoted, as in the previous configuration,upon contacting an object located below the waterline, or by operatorcontrol. Although various coupling configurations will readily come tomind, FIG. 37 shows that foil strut 708 may be mounted pivoting means,which, in FIG. 37, is illustrated as a short leg fixed to and dependingdownwardly from motor housing 706 using a pivoting connection, such as apin rotatably retained in bores, or through the use of bearings and atransverse pin or axle. A hinge-like device, a U-joint type device, orany other coupling that permits pivoting of the foil strut about atransverse axis could readily be used as an alternative construction.

[0163] Turning to FIG. 34, the foil strut 708 may preferably besupported by a linkage to main strut 702, in which a link 752 ispivotably connected to foil strut 708 at one end of the link 752, and isslidingly received and retained in a recess 754 disposed at an undersideof the main strut 702. The recess may be sized such that it will dictatethe range of travel of the foil strut 708. It can be seen in FIG. 34that, as foil strut travels to its extended position, link 752 isbrought toward the front of the main strut 702, where motor housing 706is disposed. The recess 754 will preferably present an obstacle tofurther forward movement of the upper end of link 752, there bypreventing further extension or pivoting of foil strut 708 in adirection away from main strut 702 and operator platform 704.

[0164] As noted previously, the control of the position of the foilstrut relative to the main strut can be achieved by linkages to thecontrol column, or by more automated means, such as the use of the jackscrew motor 755.

[0165] Similarly, as foil strut 708 moves to its retracted position, theupper end of link 752 travels toward the rear of the main strut 702.Preferably, the recess presents an obstacle to further rearwardmovement, which thus limits the range of travel of the foil strut 708 inthe direction toward the main strut 702. This range of travel maypreferably permit the foil strut to closely approach the main strut, butit is preferable that the foil strut, and particularly the propulsionmeans 730, be kept from contacting the main strut 702 and/or theoperator platform 704.

[0166] Alternative configurations for linkages between main strut 702and foil strut 708 are depicted in FIGS. 38 and 39. In FIG. 38, thelinkage 752 is pivotably connected to main strut 702, and slidinglyengages slot or slide element 784 disposed on the foil strut 708. Thisis essentially a reversal of the linkage shown in FIG. 34, however, thelinkage will function is the same basic manner. In FIG. 39, a hydraulicram 780 is provided in lieu of the linkage 752 and slot or slide 754.Either of these actuators or control elements can be employed in both ofthe basic configurations shown in FIGS. 34 and 37. In FIG. 34, the foilstrut is fixed to the motor housing, and the motor housing may rotaterelative to the main strut 702. In FIG. 37, the foil strut 708 pivots,and the motor housing remains stationary relative to the main strut.

[0167]FIGS. 35 and 36 are top plan views of two alternative preferredconfigurations of the main strut 72 of the present invention. FIG. 35illustrates that the main strut 702′ may have a front fork 760, witharms 762, 764 extending around opposing sides of motor housing 706. Thearms may preferably have pins 766, 768 held in bearings (not shown)mounted on or through the arms 762, 764, which extend into or attach tomotor housing 706, whereby motor housing 706 my rotate relative to themain strut 706 about a transverse axis.

[0168]FIG. 36 illustrates a variant on the main strut of FIG. 35,wherein the main strut 702″ has only a single arm 770 extending to oneside of the motor housing 706. The arm 770 may have a transverse pinextension 772 which is rotatably secured to motor housing 706, as shownschematically.

[0169] Either of these configurations is feasible from a technicalstandpoint. The important consideration is that the mounting of themotor housing 706 to the main strut 702, in combination with the controlmechanism for changing the orientation of the foil strut 708 relative tothe main strut, will allow a rapid release and rotation of the foilstrut under either operator command or as a consequence of an impact.

[0170] Reverting back to FIGS. 32A-C, the saddle-type operator platformillustrated in those figures shows a further enhancement in the designof the operator platform.

[0171] The saddle-type platform 740 in this embodiment is provided withrigid or semi-rigid chap-like extensions 748 around the leading edge ofthe saddle seat 740. The chaps 748 provide smooth, hydrodynamic flowaround the legs of the operator, which will be positioned behind thechaps. The chaps will aid in shielding the operator from the waterstriking those areas during al phases of operation of the craft. Thechaps 748 will also aid in bracing the operator in position on thevehicle, should a portion of the saddle strike the surface of the water,for example, when executing highly banked turns. In all, the chaps 748reduce the overall drag of the vehicle, and reduce drag-induced stresson the operator, leading to more efficient and enjoyable operation ofthe craft.

[0172] In general, it is anticipated that electronic and computer drivencontrols and actuators may be used to either supplement or replace thevarious mechanical linkages illustrated in the various drawing figures.Specific examples include the use of an electromechanical actuation ofclutch 715, using switches to detect brace 714 encountering the ends ofslot 711. As noted previously, a small motor and screw jack assembly orhydraulic ram could be used to move brace 752 to position the foilstrut. The cog 705 and pawl 713 arrangement in FIG. 33 could employ asmall motor and screw to actuate the cogs 705. The pivoting of the motorhousing or foil strut in the various embodiments could further beaccomplished and controlled by hydraulic means, or by cables undertension.

[0173] It is to be understood that the foregoing description of thepreferred embodiments of the present invention is for illustrativepurposes, and many variations or modifications may become apparent, uponreading this disclosure, to those of ordinary skill in the art. Inparticular, while the strut assembly, the operator platform, the mainfoil assembly, the control subassembly and the propulsion subassemblyhave been described as separate units that are joined together, it isenvisioned that any two or more of these subassemblies or components,and even the entire craft, may be formed as an integral or unitaryassembly. Such embodiments are regarded as being within the spirit andscope of the present invention. Those and other such variations andmodifications are intended to fall within the spirit and scope of thepresent invention, and the scope of the invention is to be determined byreference to the appended claims.

What is claimed is:
 1. A hull-less personal water craft comprising: amain strut assembly having a forward end and a rearward end, said mainstrut assembly including a motor housing disposed at said forward end;an operator platform positioned at said rearward end of said main strutassembly, said operator platform being so constructed and arranged to becapable of providing hydrodynamic lift in a fluid medium; a motorprovided in said motor housing; a foil strut operatively coupled to saidforward end of said main strut assembly and extending downwardly andrearwardly therefrom; at least one foil operatively coupled to said foilstrut; a control column having a proximal end operatively coupled tosaid main strut assembly, and a distal end having an operator interfacethereon; and a propulsion system.
 2. A hull-less personal water craft asrecited in claim 1, wherein said foil strut is rotatable about atransverse horizontal axis relative to said main strut assembly.
 3. Ahull-less personal water craft as recited in claim 2 wherein said foilstrut is coupled to said motor housing in a substantially fixedrelation, and wherein said motor housing is rotatable about a horizontalaxis relative to a remainder of said main strut assembly.
 4. A hull-lesspersonal water craft as recited in claim 2, wherein said control columnis pivotably connected to said main strut assembly, and wherein saidcontrol column is operatively coupled to said foil strut in such amanner that a pivoting of said control column controls the rotation ofsaid foil strut.
 5. A hull-less personal water craft as recited in claim4, wherein said at least one foil is pivotably connected to said foilstrut, and said control column and said at least one foil areoperatively coupled such that an attitude of said at least one foil iscontrolled by said control column.
 6. A hull-less personal water craftas recited in claim 3, wherein said main strut assembly furthercomprises a forked strut having two arms extending forwardly to form ayoke around said motor enclosure, and wherein said motor enclosure ispivotably mounted to said two arms.
 7. A hull-less personal water craftas recited in claim 3, wherein said main strut assembly furthercomprises a forked strut having a single arm extending forwardly to forma half-yoke at one side of said motor enclosure, and wherein said motorenclosure is pivotably mounted to said single arm.
 8. A hull-lesspersonal water craft as recited in claim 2, wherein said motor housingis maintained in a substantially fixed position relative to a remainderof said main strut assembly, and wherein said foil strut is pivotablycoupled to said motor housing, so as to be rotatable relative to saidmain strut assembly.
 9. A hull-less personal water craft as recited inclaim 8, wherein said control column is pivotably connected to said mainstrut assembly, and wherein said control column is operatively coupledto said foil strut in such a manner that a pivoting of said controlcolumn controls the rotation of said foil strut.
 10. A hull-lesspersonal water craft as recited in claim 9, wherein said at least onefoil is pivotably connected to said foil strut, and said control columnand said at least one foil are operatively coupled such that an attitudeof said at least one foil is controlled by said control column.
 11. Ahull-less personal water craft as recited in claim 1, wherein said atleast one foil is pivotably connected to said foil strut, and isoperatively coupled to said control column such that an attitude of saidat least one foil is controlled from said control column.
 12. Ahull-less personal water craft as recited in claim 2, wherein saidoperator platform is substantially saddle-shaped, and wherein said foilstrut is sized such that, when pivoted upwardly toward said main strutassembly, said distal end of said foil strut rotates into a cavityformed at an underside of said operator platform.
 13. A hull-lesspersonal water craft as recited in claim 12, wherein said operatorplatform has a foil mounted across a rearward end of said cavity.
 14. Ahull-less personal water craft as recited in claim 12, wherein saidoperator platform has two integral chap extensions at a forward end ofsaid operator platform.
 15. A hull-less personal water craft as recitedin claim 1, wherein said operator platform is substantiallysaddle-shaped and has two integral chap extensions at a forward end ofsaid operator platform.
 16. A hull-less personal water craft as recitedin claim 1, wherein said propulsion system includes a propeller shaftcontained within said foil strut, said propeller shaft being operativelycoupled to said motor.
 17. A hull-less personal water craft as recitedin claim 16, wherein said propulsion system further comprises an openpropeller operatively coupled to said propeller shaft, and disposed atsaid distal end of said foil strut.
 18. A hull-less personal water craftas recited in claim 17, wherein said propulsion system comprises anenclosed propulsor operatively coupled to said propeller shaft, anddisposed at said distal end of said foil strut. 19, A hull-less personalwater craft as recited in claim 1, wherein said propulsion systemcomprises a duct for pumping water through said foil strut, and a nozzlepositioned on the foil strut for discharging the water from the foilstrut.
 20. A hull-less personal water craft as recited in claim 2further comprising a foil strut positioning device.
 21. A hull-lesspersonal water craft as recited in claim 20, wherein said foil strutpositioning device comprises a link element pivotably coupled to saidfoil strut and operatively coupled to said main strut assembly in amanner permitting said link element to move forwardly and rearwardlyalong a portion of said main strut assembly.
 22. A hull-less personalwater craft as recited in claim 20, wherein said foil strut positioningdevice comprises a link element pivotably coupled to said main strutassembly and operatively coupled to said foil strut in a mannerpermitting said link element to move along a portion of said foil strut.23. A hull-less personal water craft as recited in claim 20, whereinsaid foil strut positioning device comprises a hydraulic ram operativelycoupled to said foil strut and to said main strut.
 24. A hull-lesspersonal water craft as recited in claim 3, further comprising a foilstrut positioning device.
 25. A hull-less personal water craft asrecited in claim 24, wherein said foil strut positioning devicecomprises a brace attached at one end to said motor housing, and at theother end to said control column.
 26. A hull-less personal water craftas recited in claim 25, wherein said brace slidingly engages a slotprovided in said control column, whereby said control column may bemoved within a predetermined range of movement without moving said motorhousing, and wherein, upon said brace traveling to an end of said slot,said control column is operable to rotate said motor housing.
 27. Ahull-less personal water craft as recited in claim 24 wherein said foilstrut positioning means comprises a plurality of gear teeth coupled tosaid motor housing, and means for engaging and moving said gear teeth.28. A hull-less personal water craft as recited in claim 24, whereinsaid foil strut and said motor housing are biased to an initialretracted position, and said foil strut positioning means comprises acable assembly connected to said motor housing, and being so constructedand arranged to overcome said initial bias to move said foil strut awayfrom said retracted position.